$5.00
http://www.sweet-vapes.com/shop?pag..._color_plus.tpl&product_id=237&category_id=27
"To use the multimeter: Plug the black (negative) lead into the last plug on the bottom, and the red (positive) into the plug above that. Leave the 10A DCA plug empty.
To test ohms: Set the meter at the lowest ohm setting. Check if it reads zero by touching the leads together. If it’s not zero just subtract the amount displayed from the final measurement. Put the positive lead in the center of your atomizer connection, and the negative on the threads. Take the reading once the numbers settle down, and subtract the number from before. This is your resistance.
To test voltage: Set the meter to the lowest voltage setting (DCV 20). Put the positive lead in the center of your batteries connection, and the negative on the threads (or outside threads for an ego/riva type). Push the button to activate the device, and you should have your reading. This is the unloaded voltage."